clobbered

[Andy Jacobson]

Howdy,

        When creating oct files, sometimes the compiler spews out a
        bunch of warnings like:

corto:Šþ/ibex/nlo> mkoctfile -v amebsa.cc
c++ -c -fPIC -I/usr/local/include -I/usr/local/include/octave-2.0.16 -mieee-fp 
-fno-rtti -fno-exceptions -fno-implicit-templates -g -O2 -Wall amebsa.cc -o 
amebsa.o
amebsa.cc: In function `class octave_value_list Famebsa(const class 
octave_value_list &, int)':
amebsa.cc:48: warning: variable `int iter' might be clobbered by `longjmp' or 
`vfork'
amebsa.cc:51: warning: variable `int targiter' might be clobbered by `longjmp' 
or `vfork'
amebsa.cc:53: warning: variable `int i' might be clobbered by `longjmp' or 
`vfork'
amebsa.cc:53: warning: variable `int ihi' might be clobbered by `longjmp' or 
`vfork'
amebsa.cc:53: warning: variable `int ilo' might be clobbered by `longjmp' or 
`vfork'
amebsa.cc:54: warning: variable `double ylo' might be clobbered by `longjmp' or 
`vfork'
amebsa.cc:54: warning: variable `double ynhi' might be clobbered by `longjmp' 
or `vfork'
amebsa.cc:87: warning: variable `int n' might be clobbered by `longjmp' or 
`vfork'
/usr/local/include/octave/Array.h:194: warning: variable `int n' might be 
clobbered by `longjmp' or `vfork'
...for another 30 lines or so.

       I use the same template .cc file for different codes, but only
       some of them give this set of warnings.  They do this quite
       robustly.  Can anyone explain why this is happening, and need I
       be concerned that my variables ARE being clobbered?

       The .cc file, containing two functions, follows.  Since it is an
       adaptation of copyrighted material, I have removed the core of
       the routines, leaving the entrance/exit stuff and variable
       declarations. 

       Thanks,

                Andy



// adapted by Andy Jacobson for .oct
// original implementation from Numerical Recipes in C by Press et al.

#include <octave/pager.h>
#include <iostream.h>
#include <octave/oct.h>
#include <octave/pt-fvc.h>
#include <math.h>
#include <octave/f77-fcn.h>

// The chi-squared function we are minimizing is positive semi-definite.  Signal
// a violation of constraint with a negative return value. 

#define CONSTRAINT_NOT_VIOLATED(y)      (y >= 0)        
#define CONSTRAINT_WAS_VIOLATED(y)      (y < 0) 



double amebsa_try(Matrix &p, ColumnVector &y, ColumnVector &psum, int ndim, 
ColumnVector &pb,
                  double *yb, int ihi, double *yhi, double fac);

extern "C"
{

  int F77_FCN (dgenunf, DGENUNF) (const double&, const double&,
                                  double&);
}


double tt;
static tree_fvc *funk;
octave_value_list *fin,fout;

DEFUN_DLD(amebsa, args, nargout,
          "[p,y,iter,pb,yb]=amebsa(p,y,ndim,yb,ftol,funk,iter,temptr)") {

    // convert arguments to expected values
  Matrix p=args(0).matrix_value();
  ColumnVector y=args(1).vector_value();        
  int ndim=(int)args(2).double_value();
  double yb=args(3).double_value();
  double ftol=args(4).double_value();
  funk = is_valid_function (args(5), "amebsa", 1);
  int iter=(int)args(6).double_value();
  double temptr=args(7).double_value();

  int targiter=iter,diter=(int)floor(iter/10);
  double ranval=0;
  int i,ihi,ilo,j,m,n,mpts;
  double rtol,sum,swap,yhi,ylo,ynhi,ysave,yt,ytry;
  mpts=ndim+1;

  octave_value_list retval;

  if (! funk) {
    error ("No valid function found.");
    return retval;
  }

  fprintf(stdout,"T: %8g [",temptr);
  flush_octave_stdout();

  ColumnVector psum(ndim),pb(ndim);

<STUFF DELETED>


  octave_stdout << "] rtol = " << rtol << 'ŠÜn' ;
  flush_octave_stdout();

  retval(0)=p;
  retval(1)=y;
  retval(2)=(double)iter;
  retval(3)=pb; 
  retval(4)=yb;

  return (retval);
}

#undef AMEBSA_GET_PSUM

double amebsa_try(Matrix &p, ColumnVector &y, ColumnVector &psum, int ndim, 
ColumnVector &pb,
                  double *yb, int ihi, double *yhi, double fac) {

  double ranval=0;
  int j;
  double fac1,fac2,yflu,ytry;

  ColumnVector ptry(ndim);
  fin = new octave_value_list;

<STUFF DELETED>

  return yflu;
}

  



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